1. Technical Field:
This invention relates to a method and apparatus for providing a visual indication of refractory erosion in a refractory lined metallurgical vessel.
2. Description of the Prior Art:
Prior Devices of this type are respresented by U.S. Pat. Nos. 3,078,707 on a thickness gage for a blast furnace wall, 3,898,366 on a metallurgical heating system with refractory wear indicia and 4,269,397 on a method for measuring the thickness of a refractory in a metallurgical apparatus.
In U.S. Pat. No, 3,078,707 the thickness gage comprises a pair of electrical conductors carried in a furnace wall perpendicular thereto. The conductors being spaced apart and having a plurality of resistance elements of pre-determined resistance connected therebetween in spaced relation to one another. As the furnace wall is eroded, electrical currents connected with the electrical conductors flows through the resistance elements which have different values so that the electrical current will vary depending upon the number of the resistance elements remaining in the eroding wall.
U.S. Pat. No. 3,898,366 positions electrical conductor members in the refractory lining of the metallurgical vessel so that the metal being processed forms conducting bridges between the exposed portions of the remaining electrical conductors to provide an indication of the remaining thickness of the refractory lining.
U.S. Pat. No. 4,269,397 measures the thickness of an eroded refractory lining in metallurgical apparatus by providing a central metallic electrical conductor and an outer metallic sheath spaced from a central conductor positioned in the linin so as to be subject to erosion thereof. The device erodes at substantially the same rate as the refractory and is conected by electrical connector means to an electronic instrument capable of generating stepped timed voltages or pulses through the device and receiving reflected pulses or echoes which may be visually displayed and the characteristics of which will indicate the length of the monitoring device which is substantially the same as the thickness of the refractory in which it is positioned.